Polymers, whether naturally occurring or synthetic, are generally included in personal care products, including hairsprays, shampoos, hair conditioners, skin creams, skin lotions, cosmetic products, antiperspirants, deodorants, shaving creams, topic drug compositions, sunscreen products, and the like, because of their rheological, holding, and film-forming properties.
Derivatives of naturally occurring polymers can provide chemical and physical properties that differ from the naturally occurring polymer. For example, cellulose and guar derivatives have been derived from chemical reaction with a variety of compounds, including ethylene or propylene oxide, sodium monochloroacetate, and quaternary reagents. Some of these derivatives produce substances that are solvent compatible, have greater clarity in solution as compared with the non-derivatized form, hydrate faster and have greater temperature stability. As a result these derivatives have improved use for liquid formulations. For example, cationic starch derivatives are important in the paper industry as wet-end additives where they act to increase dry strength. The chemical properties of the derivatives depend upon the base material being derivatized and upon the derivatizing reagent with which they are reacted. Derivatization with a cationic reagent can lend charge to a base polymer, providing the efficacy in the application that would otherwise be absent, e.g. cationic groups improve adhesion to polar substrates. Derivatization with a cationic reagent generally involves the use of either water-based or solvent-based, hydroxide catalyzed reactions, as described in the technical literature available from the suppliers of such reagents.
Quaternary ammonium (also referred to as "quaternized") derivatives of a number of commercially available polymers are known in the personal care industry to enhance substantivity (i.e., cling and resistance to removal upon rinsing with water) to anionic sites within hair or skin. Quaternized derivatives of cellulose, guar, and starch, for example, can be found in many personal care products.
The degree of substitution (D.S.), of derivatized polysaccharide polymers generally ranges from 0.05 to 0.25. The mode of reaction for polysaccharide polymers is typically through the hydroxyl groups associated with the sugar rings on the polysaccharide polymers. In one example, derivatization of polysaccharide polymers with ethylene or propylene oxide is catalyzed by a base hydroxide to yield polymer derivatives with a substitution level of one to fifty percent by weight of ethylene or propylene oxide. Ethylene or propylene oxide derivatized polysaccharide polymers have been used in the personal care area. In another example, double derivatives of starch, cellulose or guar can also be prepared, for example, using a quaternary amine.
In the industrial arena, hydroxypropyl cellulose and/or guar have been used as viscosifying agents for oil well drilling, oil well stimulation, fire fighting, textiles, paints and other applications. Derivatization of sugar containing polymers with sodium monochloroacetate (for example, to produce carboxy-methyl derivatives) yields anionic polymers that are also useful in industrial applications. For cxaiiplc thcsc derivatives function as wet strength additives in papermaking or in textile sizing. Hydroxypropyl methylcellulose has also been used in the cosmetic and personal care industries.
Typically, a derivatized polysaccharide polymer can also function as a viscosifying agent. Very low concentrations of any of the above derivatives can impart a high viscosity to a solution to which the derivatives are added. This is particularly true for solutions have some starting measurable viscosity. As a result of the added viscosity imparted by the derivatized polysaccharide polymer there is generally a low upper limit to the amount of derivatized polysaccharide polymer that can be added to these solutions. In addition, derivatized polysaccharide (including sugar and starch polymers) are typically salt and pH sensitive. Therefore, solutions containing these polymers are stable over limited salt concentration ranges and over narrow pH ranges. In addition, the derivatized polymers are often shear sensitive and generally non-Newtonian in that their apparent viscosity is lower with increased shear. When these polysaccharide polymers are added to an existing composition, the rheology of the composition typically increases and the solution also becomes shear sensitive. Adding functionality (i.e., substantivity, solvent compatability, pH compatability, or the like) through the addition of a derivatized polymer, therefore, typically has a potential negative rheological effect upon the entire composition.